Automatic lathe chuck



June 28, 1949. J. F. MARSHALL AUTOMATIC LATHE CHUCK Filed July 10, 1945c/Zr mes i. Mars/tall Patented June 28, 1949 UNITED STATES PATENT OFFICEAUTOMATIC LATHE CHUCK James F. Marshall, Newton, Iowa Application July10, 1946, Serial No. 682,496

2 Claims.

The present invention relates to new and useful improvements in lathechucks and more particularly to a device of this character actuated bycentrifugal action to automatically grip the work for holding the sameon the machine for rotation therewith.

An important object of the invention is to provide a device of thischaracter in which its gripping action on the work is increased inaccordance with an increase in the speed of the machine.

A further object of the invention is to provide an automatic lathe chuckwhich simplifies and reduces the loading and unloading time required forthe work whereby to promote economy on mass production jobs.

A still further object is to provide a device of this character whichmay be easily and quickly attached to a face plate of a lathe or othermachines, or which may be secured to a lathe spindle.

Another object is to provide a device of this character simple in factfor construction and which is efficient and reliable in operation,relatively inexpensive to manufacture and otherwise well adapted for thepurposes for which the same is attempted.

Other objects and advantages reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming part hereof, wherein likenumerals refer to like parts throughout, and in which:

Figure 1 is a front elevational view.

Figure 2 is a side elevational view.

Figure 3 is a sectional view taken on line 3--3 of Figure 2.

Figure 4 is a transverse sectional view taken on line 4-4 of Figure 1.

Referring now to the drawings in detail wherein for the purpose ofillustration I have disclosed a preferred embodiment of invention, thenumeral 5 designates an attaching plate of a disk form having boltopenings at 6 therein for attaching the plate to the front surface of aface plate I of a conventional construction and which is mounted forrotation on a lathe or other machines.

A pair of semi-circular jaws 8 and 9 are positioned against the outersurface of the attaching plate 5, the jaw 8 being secured thereto in astationary position by bolts or screws III.

A pair of guide pins II have one end recessed in the ends of thestationary jaw 8 while the other ends of the pins are slidably receivedin recesses l2 of the movable jaw 9. Coil springs I3 are positioned inthe recesses l2 behind the pins H to urge the jaws 9 into an openposition, the jaws cooperating to grip the work or stock in the openingM at the center of the jaws. A spring projected ball I5 is carried bythe movable jaw 9 to bear against the work to hold the same in themachine while the machine is gaining speed.

A pair of semi-circular dogs l6 and I1 surround the jaws 8 and 9, oneend of the dogs being pivoted to the attaching plate 5 by pins or thelike IS, the dogs preferably being of heavy metal or weighted to swingthe free ends of the does away from the jaws by centrifugal actionduring rotation of the machine.

The ends of the dogs I6 and I! are positioned at degrees with respect tothe free ends of the jaws 8 and 9 as shown in Figure 3 of the drawingsand with the free ends of the dogs positioned adjacent the outerperiphery of the stationary jaw 8, thus bringing the pivoted ends of thedogs adjacent the outer periphery of the movable jaw 9 and at pointssubstantially intermediate the ends of the latter.

The inner periphery of the dogs l6 and I1, at their pivoted ends, areprovided with recesses l9 in which rollers 28 are journaled with oneside of the rollers exposed at the inner corner of the dogs at thepivoted ends thereof. The axes of the rollers 28 are positioned closerto each other than the axes of the pins l8 whereby an outward swingingmovement of the free ends of the dogs l6 and I! will cause a radialinward movement of the rollers 20 whereby to bear against the movablejaw 9 to thus contract the opening Ill and cause a gripping engagementof the jaw 9 with the work or stock positioned therein. An increase inthe speed of rotation of the machine will increase the gripping actionof the dogs l6 and IT on the jaw 9 to thus firmly hold the work inposition on the lathe.

Upon stopping of the machine the free ends of the dogs l6 are movedtoward a closed position for releasing the rollers 20 by means of pins2| recessed in the periphery of the dogs and projecting substantiallyradially therefrom and connected to each other by means of a coil spring22.

Of the foregoing it will be apparent that the movable jaw 9 is normallyheld in an open position by means of the springs l3 and spring 22releasing pressure on the movable jaw by the rollers 28 whereby the endof the work may be easily and quickly placed in the opening I4 andremoved therefrom. When the machine is rotated the dogs It and I! willswing outwardly whereby to exert pressure on the movable jaw 3 9 by therollers 20 and clamp the work in position between the jaws.

In view of the foregoing description taken in conjunction with theaccompanying drawings it is believed that a clear understanding of thedevice will be quite apparent to those skilled in this art. A moredetailed description is accordingly deemed unnecessary.

It is to be understood, however, that even though there is herein shownand described a preferred embodiment of the invention the same issusceptible to certain changes fully comprehended by the spirit of theinvention as herein described and the scope of the appended claims;

'4 said member, one jaw being fixed thereon and the other jaw beingmovable toward the fixed jaw, spring means biasing said movable jaw awayfrom the fixed jaw, a pair of rollers upon opposite sides of thetransverse center of the movable jaw, and means responsive tocentrifugal action to move said rollers circumferentially of the movablejaw tangentially thereof for moving the movable jaw toward the fixed jawin opposition to said spring means.

JAMES F. MARSHALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 87,929 Hawkins Mar. 16, 1869846,193 Fellows Mar. 5, 1907 1,149,148 Miller Aug. 3, 1915 1,430,689Schroeder et al. Oct. 31,1922 2,420,128 Fisher May 6, 194. 7.

FOREIGN PATENTS Number Country Date "481,505 France Sept. 1916

